The present invention relates to a fuel cell system, and specifically, relates to a technology to activate a fuel cell without degrading components of the fuel cell and without discharging fuel gas to the outside.
In a general polymer electrolyte fuel cell (hereinafter, abbreviated as a fuel cell), while power generation is stopped, oxidant gas flows from a cathode into an anode through a polymer electrolyte membrane, and a gas mixture of the oxidant gas and fuel gas is generated in the anode. In such a background, as disclosed in the Japanese Patent Laid-Open publication No. 11-97047, in a conventional fuel cell system, the oxidant gas and fuel gas are purged with nitrogen gas while power generation is stopped. In activation of the fuel cell, operating pressure on the anode side is increased, and then the oxidant gas is supplied to the cathode. Subsequently, an exhaust valve is opened to discharge the nitrogen gas and gas mixture remaining in the anode.